Power transmission



Aug. 14, 1945. I E. L. ROSE 2,382,027

POWER TRANSMISSION Original Filed July 5, 195a 4 sheets-sheer 1 FIG. I

IINVENTOR -EDWIN L- ROSE v I v BY% I ATTORNEY Aug. 1 4, 1945. E. LHROSE2,382,027

POWER TRANSMIS S ION Original Filed July 5, 1938 4 Sheets-Sheet 2 I NVEN TOR Aug. 14, 1945. E; ROSE 2,382,027

POWER TRANSMISSION 7 Original Filed Juiy'5, 1958 4'SheetsSheet 3 4 v IFIG. 3

ISO

0 304 328 we I 11 II 184- Q I ii 188 1h ao.--- I -\ss INVENTOR EDWIN L.ROSE -BY A JKVM ATTORNEY Patented Aug. 14, 1945 POWER TRANSMISSION EdwinL. Rose, Woodbury, Conn.

Original application July 5, 1938, Serial No.

217,395, now Patent No. 2,265,314, dated Decemher 9, 1941. Divided andthis application April 25, 1941, Serial No. 390,237

3 Claims.

This invention relates to power transmissions and particularly totransmissions of the hydraulic type comprising a fluid pump and fluidmotor either or both of which may be provided with mechanism for varyingits displacement in order to vary the speed ratio between the primemover which operates the pump and the load device which the motoroperates. This application is a division of my copending applicationSerial No. 217,395, filed July '5, 1938, now Patent No. 2,265,314, whichin turn is a division of my copending application, Serial No.- 90,'785,filed July 15, 1936, for Power transmission, now Patent No. 2,168,655.The invention is illustrated as adapted for use in a well drilling rigof the well-known type in which a string of drill stem is caused torevolve by a rotary drilling head while a portion of the weight of thestring rests upon the earth formation at the bottom of the hole beingdrilled, the remainder being suspended on a block and falls mounted in adrilling derrick'and connected to a draw-works drum.

It is desirable in such drilling operations to maintain at a constantvalue that portion of the weight of drill string which rests upon theearth formation at the bottom of the hole and to be able to readilyadjust such weight to different values as different formations areencountered. Various automatic control devices have been proposed forregulating the weight on the drill stem, many of which have beenunsatisfactory, due to lack of sensitivity in their regulation. Someforms of automatic regulation utilize mechanism which isresponsive tovariations in tension in either the live or the dead end of the cable,which supports the drill string through the block and falls. Suchdevices may not be made sensitive to the degree required since thefriction of the sheaves introduces a damping effect which in someinstances may be as high as 25% of the suspended weight. Such a devicetherefore can respond only to changes in suspended weight which aregreater in magnitude than the frictional damping effect between thedrill string stem and the weight sensitive device.

In earth boring operations of this general class it is necessary fromtime to time as the work progresses to retract the drill stem from thehole for the purpose of replacing the cutting bit at the lower end ofthe drill stem. In so doing it is necessary to stop the rotationalmovement of the drill stem and hoist the stem a suitable distance tonear the top of the derrick, this distance usually being 90 feet, and togrip the stem at the rotary table and remove the section of the drill 66only on the first hoist at a given ratio and that stem projecting abovethe table. The hoisting apparatus is then lowered and connected to theremaining portion of the stem projecting from the rotary table, andhoisted another feet and the operation is repeated until the entirestring is removed from the hole. After necessary repairs to the bitaremade, by reversing this proc- 'ess the bit may be again brought toworking posi tion at the bottom of the hole. I

In many drilling operations of this nature it is of prime importancethat the hole be cut down to its intended depth in the least possibletotal lapsedtime. Inasmuch as normal drilling operations are suspendedwhile the drill string is being retracted and replaced for repairpurposes, it is essential to keep the time consumed for this purpose toa minimum and it is customary to provide prime movers of several timesthe power output required for drilling operations so that the string maybe retracted at a maximum speed and lost time reduced to a minimum. Itwill be seen that in retracting the string the weight of the string andthe load to be lifted is progressively reduced as each section of drillstem is detached from the sections below it so that at each hoist of 90feet the load to be hoisted is reduced by the weight of one 90-footsection of drill stem.

For a given maximum horsepower of the prime mover and a given weight ofdrill string there is only one speed ratio between the prime mover andthe draw-works drum whichwill permit the string to be retracted at aspeed which utilizes the full power of the prime mover. It is obvispeedratio for a considerable number of consecu-' tive hoists of the drillstem before the drill stem weight is reduced sufiiciently to enable theoperator to shift to the next higher ratio. It will be seen that withthis method of operation the speed of hoisting is the same for severalconsecutive hoists of the drill stem and inasmuch as the weight of thestem is reduced at each hoist, the full power ofthe prime mover can beutilized 2 aseaoav thereafter the power load on the prime moverprogressively decreases.

It is an object of the present invention to provide a power transmissionincorporating an automatic feed control for maintaining constant weighton the bit at the bottom of the hole, which is responsive directly tothe suspended weight and which operates with a high degree' ofsensitivity to small changes in the suspended weight.

A further object is to provide a power transmission suitable for use asa draw-works drive for a well drilling rig whereby the ratio of powertransmission between the prime mover and the connection which is, in thepresent invention,

suitable swivelling connection at 96 is provided for permittingcirculation of themud laden cutting draw-works drum may be adjusted tothe valuenecessary to utilize the full power output of the prime moverat each hoist of the drill stem.

A further object is to provide a power transmission of such characterwherein an operatorcontrolled member may be moved to cause thedraw-works drum to rotate in hoisting direction and wherein automaticmeans beyond the control of the operator acts to select the proper ratioof power transmission necessary to utilize the full power output of theprime mover for any given weight of drill stem.

It is also an object to provide a power transmission for a well drillingapparatus incorporating an automatic weight sensitive feed control fordrilling, together with an automatic constant horsepower control forhoisting, wherein readily operable controls of a simple and reliablenature are provided for shifting operation of the apparatus betweendrilling and hoisting and viceversa.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to theaccompanyingdrawings wherein a preferred form of the present invention is clearlyshown.

In the drawings: Figure 1 is a 'cross sectional view of a powertransmission incorporating a preferred form of the. present invention.

Figure 2 is a diagrammatic view of the hydraulic circuits employed inthe invention. 1 Figure 3 is a fragmentary side view of a hydraulicpower transmission forming part of the a variable displacement fluidpump 32. The output shaft 30 of the motor may be connected by sists of avariable displacement fluid motor 20 and suitable driving connections,shown more fully in my aforesaid Patent No. 2,168,655, to a drawworksdrum while the input shaft 34 of the pump maybe connected by otherdriving connections to a suitable prime mover such as 9. Diesel engine.

The details of the drilling rig being of no concern in the presentinvention, they are-not illustrated herein. Normally such a rigcomprises a draw-works or winch by which the tool string 'may beraisedor lowered-in the hole together with suitable rotary driving meanswhereby the "kelly or squared section at the top end of the string maybe rotated. The tool string issuspended from a block and falls in thederrick by means of a swivel fluid to the interior of the tool string.The power transmission and control system therefor includes a strokevarying hydraulic motor 92 for the variable displacement pump 32 and astroke varying hydraulic motor 94 for the variable displacement motor20. The motor 28 and pump 3-2 are illus trated as of the Waterburyconstruction comprising revolving cylinder barrels within which pistons98 are reciprocated by the motion of socket rings I 00 which revolve intilting boxes I02 and I04.

The tilting box I02 carries a stud I05 having a pivoting and slidingconnection with a difierential piston I00 mounted in cylinder bores H0and I I2 of the hydraulic motor 92. The bore H2 is subjected to aconstant fluidpressure from an auxiliary pump II4 (see Figure 2),through a con- .duit IIB while the bore H0 is subjected either topressure responsive pilot valve I26 at certain times, and at other timesis subjected constantly to auxiliary pump pressure.

A movable valve member I20 of the pilot valve I26 is mounted in a boreI30 of the pilot valve I26 and has a reduced diameter stem I32projecting through the bottom wall of the bore I30 and carries twopiston heads I34 and I30. The lower end of the bore is in communicationthrough a conduit I39 with the working circuit of the hydraulictransmission preferably through a shuttie valve I40 as indicated inFigure 2 whereby the side of the working circuit which is of higherpressure at any instant is placed in communication with the lower end ofthe bore I30. An adjustable spring I42 urges the valve member I28downwardly against the pressure exerted in the lower end of the boreI30. A conduit I44 is normally closed by the piston I30 and is opened tothe exhaust side pressure at the interior of the case of the motor 20through a passage I46 when valve member I23 moves downwardly whilecommunication is established between conduit I44 and the auxiliary pumpII4 through' a conduit I40 when the valve member I20 is moved upwardly.

- The fluid motor 92 is under the control of a manually operablefollow-up valve I50 which comprises a plunger I52 'slidable in a boreI54 formed in the small end of the piston I00. The bore I54 is incommunication with the interior of the case ofthe pump 32 through apassage I56. The plunger I52, is formed with a groove I58 communicatingwith the bore I54 by a passage I60 and a groove I 62 communicating withthe cylinder bore II2 through a passage I64. The piston I08 formed witha bore I06 leading from the cylinder II to a groove I58 ,(see Figurewhich connects a radial bore I with a diametrically opposite radial boreI 12. Longitudinal movement of the plunger I52 in either direction fromthe position illustrated thus opens a connection either from-thecylinder bore I I2 or from the bore I54 to the bore I55, leading to thecylinder H0 and thus causes movement of the piston I08 in a manner tofollow up the movements of the plunger I52. The plunger I52 iscontrolled manually through a collar I41 and a fork I49 (Figure '7)which may be connected to a suitable control handle, not shown, adjacentthe drillers station.

Plunger I52 is adapted to be rotated angularly about its axis in orderto move grooves I58 and I52 out of register with the radial bores I10and I12 as illustrated in Figure fi. For this purpose, a sleeve I14 ismounted adjacent the end of the cylinder H2, and is connected to theplunger I52 by a sliding key I15. An arm I18 on the sleeve I14 may bemoved to rotate the sleeve I14 and plunger I52 as desired withoutaffecting the longitudinal position of the plunger I52.

For the purpose of automatically controlling the tilting box I02 tomaintain the horsepower delivered by the transmission at a constantmaximum, certain valves are provided capable of predominating over thecontrol exercised by the plunger I52. Referring now to Figure 2, a speedgovernor operated valve I80 is provided, having a movable member I82provided with a piston head I84 for controlling the passage of fluidbetween a conduit I85 and the interior of the casing of the pump 32. Themember I82 is operated by means of an arm I88 which is controlled by aspeed governor I90 responsive to the speed of the shaft 34 of the pump82. The arm lies in a downward position, illustrated, at normal pumpspeeds and moves upwardly whenever the pump speed falls below normal, toconnect conduit I85 with the interior of the casing through a conduit.

A piston head 200 is subjected to pressure from the shuttle valve I40through a conduit 202 which is counteracted by an adjustable spring 204so that when the pressure in either side of the working circuit risesbeyond a predetermined safe value the valve member I94 rises to connectthe conduit I98 with the interior of. the

I casing of the pump 32 through a conduit 205.

A selector valve 208 is provided for manually transferring controlbetween the automatic constant horsepower control used during hoistingof the drill stem from the well and the automatic constant weightcontrol used while drilling. For this purpose the valve 208 is providedwith a movable member 2I0 having pistons 2I2,

2I4, 2 I5 and 2 I8. A conduit 220 leads to the body of the valve 208between the pistons 214 and 2I5 and is connected to the outlet-line 222of the auxiliary pump II4.- A conduit 228 connects to the body of thevalve 208 between the pistons 2 and 2I5 and leads to the cylinder I22 ofthe motor 94. Between the piston heads 2I5 and 2I8 the conduit I44connects to the body or the valve 208. Between the piston heads 2I2 and2I4, a conduit 224 connects to the body of the valve 208 and leads to apilot control valve 225,

laterto be described. Between the heads 2I2 and 2 I4 a conduit 228connects to the valve body and leads to the cylinder H0 or the motor 92.To the left of the piston 2I2 a conduit 230 connects to the body of thevalve 208 and leads to the conduits I85 and I98. A bore, not shown, isprovided longitudinally 'through the center of the member 2 I0 forconnecting the extreme end spaces of the valve body together.

In the position of the valve 208 illustrated in Figure 2, which is theposition for constant weight control, the cylinder I 22 is subjected tocontrol by valve I25 through the conduits I44 and 223. The cylinder '0is cut off from control by the pilot valve 225 and is subjected tocontrol by the speed responsive valve I and pressure responsive valveI92 through conduits 228 and 230. The valve 208 is controlled from astem 232 which is connected toa suitable control handle, not shown,adjacent the drillers station. A control rod 238 is also connected tothe same handle and operates a bell crank 240 which is connected bymeans of alink 242 to the arm I18 of the sleeve I14 so that when thevalve 208 is moved into drilling position thesleeve I14 is turned tomove the grooves I58 and I52 out of register with the bores I10 and I12.The

- passages I50 and I54 are somewhat smaller than the passages betweencylinder I I0 and the exhaust side of the system through valves I80 andI92 so that during.constant horsepower operation, the valves I80 and I92 may predominate over the follow-up valve I50.

Referring to Figure 5 which shows the mechanism for controllingthe'weight on the drilling bit, the cylinder 84, which is mounted 'atthe top of the kelly 18, includes a cover 244 having a central borethrough which a circular stem 245 may slide, which bore is sealed with apacking member 248. The stem 245 carries the bail 80 at its upper endand is provided with a piston 250 at its lower end having a fluid tightsliding fit in the interior bore of the cylinder 84. Piston 250 carriesa valve 252 adapted to control-the passage of fluid from the top to thebottom of the piston 250. For thispurpose the piston is provided with abore 254 having an enlarged portion 255, the bore 254 being adapted toreceive a piston member 258 of the valve 252. Passages 250 extend fromthe bore 254 to the lower side of the piston 250. cordance with theposition of the piston 250 relative to the cylinder 84 by means of alever 252 pivoted at 254 and having a heel 255 adapted to rest on thebottom surface of the cylinder 84. A spring 251 constantly urges thevalve 252 downwardly and holds the heel 255 against the bottom of thecylinder 84.

A conduit 258 is formed in thestem 245 to communicate with the spaceabove the piston 250 and terminates in a pipe 258a which is connected bya flexible hose, not shown, to the transmission control mechanism. Aconduit 210 extends from the lower face of the piston 250 through thestem 245 and terminates in a pipe 210a which is connected by a flexiblehose, not shown, to the transmission control mechanism. The conduit 258is connected to the outlet of a second auxiliary pump 212 and to a port214 in the pilot valve 228. The conduit 210 is connected to the inlet ofauxiliary pump 212 and to a port 218 in the pilot valve 225. The pilotvalve 225 has a movable member 218 having piston heads 280, 282, and 284and is formed with cylindrical end portions 285 and 288 receivable inbores 290 and 292 The valve 252 is controlled in acof the valve housing.A .conduit 294 extends through the movable member 218 to connect thebores 290 and 292. An adjustable spring 296 controlled by a screw 291yieldingly urges the valve member 218 to the right. The position of themovable member 218 is' then determined by the difference in pressurebetween the conduits 268 and 210 which in turn is determined by thepressure drop across the valve 252. A conduit 216 serves as a drain forthe end chambers of valve 226.

The piston 282, when the member 218 is in mid-position is adapted toclose a port 298 comdischarge conduit 222 of the auxiliary pump -I I4.-

When the valve member 218 is moved to the left communication isestablished between the port 298 and a port 304 communicating with aconduit 306 which leads to the return conduit 308 for the auxiliary pumpII4. The conduit 308 is in communication with the usual expansion tank3I0 which is also connected by conduits, not shown, with the interior ofthe casings of the motor 28 and the pump 32.

A relief valve 3l2 connects by conduits 3l4 and 3I6 with the outlet andthe inlet of the pump I I4 for the purpose of limiting the pressuredeveloped in the conduit 222. A relief valve 3I8 is interposed in aconduit 320 leading from the conduit 302 to the conduit 210 for thepurpose of replenishing fluid in the system fed by the auxiliary pump212. The valve 3| 8 may be set so that a predetermined drop in pressurein the low pressure conduit 210 permits fluid to pass from the conduit302 to the conduit 210 until the pressure in the latter rises to normaloperating value. A relief valve 322 is also provided in a conduit 324leading between the conduit 210 and the return conduit 308 for theauxiliary pump II4. The valve 322 is preferably set to open ata'predetermined pressure rise above normal in the low pressure conduit210. Conveniently the conduit 210 may be maintained at a range ofpressures between atmospheric and 25 lbs. per sq. in. thereabove. Thusthe valve 322 would be set to relieve at 25 lbs. per sq. in. while thevalve 3 I 8 would be set to relieve at the same value at which the valve3I2 is set. The auxiliary pumps II4 and 212 may be driven from the shaft34 by a belt drive 328 while a belt drive 328 operates the speedgovernor I90.

In operation of the device when it is desired to hoist the drill stem,the selector valve 208 is moved to the lefthand position, in Figure 2,in which sleeve I14 holds the grooves I58 and I62 in register with thebores I and I12, and the speed of hoisting may be controlled by shiftingthe plunger I52. Thus; if the plunger I52 is moved to the right,Figuresl and 2, fluid will be admitted to the cylinder IIO from pump II4through the conduits 222, and H6, cylinder II2, conduit I64, groove I62,bore I12, groove I68 and bore I66. The piston I08 will thereby move tothe right by the same distance that the plunger I52 was moved to theright and the tilting box I02 will be moved into stroke in a direction.causing the hoist drum l8 to wind cable thereon and lift the drillstring. Conveniently the plunger I52 may be thrown to its limit so thatthe tilting box I02 will be moved into full stroke if the weight of thedrill string is such as to permit hoisting at as this pressure reaches apredetermined point,

for example 500 lbs. per sq. in.; valve member I28 lifts, permittingfluid from the auxiliary pump II4 to flow through conduits 222, I48 andI44,

valve 208 and conduit 223 to the cylinder I22,-

thus moving the piston I20 to the left and placing the tilting box I04in full stroke position. As the piston I08 continues to move to theright ,a

point is reached where the speed of hoisting is such that the maximumhorsepower of the prime mover is utilized. Any movement of the tiltingbox I02 beyond this point causes the prime mover to fall ofi in speedwhich accordingly operates the speed governor I90 to lift the valve I80.As soon as valve I80 lifts the cylinder 0 is opened to the exhaust sideof the system through conduits 228, valve 208, conduits 230 and I86,valve I80 and conduit I85. Movement of the tilting box I02 is thereforeprevented beyond a position at which the speed of hoisting is such as touse the full horsepower of the prime mover.

As the weight of the drilling stem is gradually decreased by progressiveremoval of sections thereof. the tilting box I02 moves further toward.

full stroke position at each time the plunger I52 'is operated to hoist.When the weight of the stem decreases sufliciently so that the tiltingbox I 02 can move into full stroke position without slowing down theprime mover, the transmission operates at one to one ratio until afurther decrease in the weight of the stem permits the valve I26 to dropthus opening the cylinder I22 to the exhaust side of the system throughconduit 223,

. valve 208, conduit I44, valve I26'and conduit I46.

The piston I20 thereby moves to the right until the strokeof the motor28 has decreased sufliciently to maintain the pressure at which thevalve I26 is set. The hoisting speed is thereby increased to the pointwhere the full power of the prime mover is utilized. As the weight ofthe stem further decreases, the stroke of, the motor 28 iscorrespondingly decreased until the minimum stroke is reached at thepoint where string.

The drill string may be fed into the hole again as sections are addedthereto by permitting the drill string to fall of its own weight in theusual manner. When the drill string has been completely. fed into thehole, drilling may be resumed by operating the handle to shift theselector valve 208 and the sleeve I14 into drilling position. Underthese conditions the auxiliary pump 212 delivers fluid through theconduit 268 through the upper chamber of the cylinder 84. suremaintained in this chamber is determined by the setting of the spring296 which may be adjusted to maintain any desired proportion of thetotal weight of the drill stem suspended from the traveling block. Asdrilling proceeds the drill stem is fed downwardly as required tomaintain the weight on the drillingbit constant. Thus as the drill makeshole the resulting small increase in the weight suspended on thetraveling blocktends to pull the cylinder 84 downwardly thus tending toclose the valve 252 and increase the pressure above the piston 250. Thevalve The pres- Y member I'll is thereby moved to the left permittingfluid to flow from the cylinder Ill through conduit Ill, valve Ill,conduit 2, port 2", port I, conduit 3" and conduit III to the exhaustside of the systenn The piston III is thereby moved to the leit inFigure 2 to move the tilting box ll! slightly into stroke in thelowering direction until the desired weight is again maintained on thedrilling bit. During normal operation the mechanism tends to reach astate of equilibrium with tilting box III in a slight stroke in thelowering direction such that the drill is fed downwardly at the samerate at which the bit "makes hole. Should the drill be led downwardlytoo rapidly the cylinder .4 will tend to rise, thus opening the valve "2wider and permitting valve member 2" to move to the right. Fluid fromthe auxiliary pump III is thus permitted to pass through the conduits222 and 102, port I", port "I, conduit I24,

valve 208 and conduit m to the cylinder H...

The rate of feed is thus adjusted to correspond circuit iormaintaining-fluid under pressure in one end oi the cylinder, a valve forvariably passing iluid from said one end of the cylinder, means foroperating said valve in accordance with relative movement between thepiston and cylinder, a valve responsive to variations in pressure insaid end of the cylinder, and means controlled by the last mentionedvalve for bodily moving the cylinder and piston assembly.

2. A fluid pressure operated control system comprising a cylinder andpiston mounted for relative movement in accordance with changes in aquantity to be controlled, a fluid pressure circuit for maintainingfluid under pressure in one to the rate at which the bit makes hole andI in a quantity to be controlled, a fluid pressure end of the cylinder,means for varying said pressure in accordance with relative movementbetween the piston and cylinder, a valve responsive to variations insaid pressure, and means controlled by said valve for bodily moving thecylinder and piston assembly.

3. A fluid pressure operated control system comprising a cylinder andpiston mounted for relative movement in accordance with changes in forcetransmitted from one to the other, a iiuid pressure circuit formaintaining iluid under pressure in one end oi the cylinder, a valve101' variably passing fluid from said one end oi the cylinder, meanstor-operating said valve in accordance with relative movement betweenthe piston and cylinder, a valve responsive to variations in pressure insaid end of the cylinder, and

means controlled by the last mentioned valve ior bodily moving thecylinder and piston assembly.

EDW'INLROBI.

